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HLS-440 Automotive Hydrogen Leak Sensor
HLS-440
1 Automotive Hydrogen Leak Sensor ................................................................................................ 3
Introduction ....................................................................................................................................... 3
Main features .................................................................................................................................... 3
2 Overview ........................................................................................................................................... 4
3 Mechanical ........................................................................................................................................ 5
Dimensions ....................................................................................................................................... 5
Installation ......................................................................................................................................... 6
4 Electrical Interface ............................................................................................................................ 7
Electrical connector .......................................................................................................................... 7
CAN bus interface ............................................................................................................................ 7
Physical interface..................................................................................................................... 7
Bus Identification...................................................................................................................... 7
Messages from the sensor ...................................................................................................... 8
Wake-Up function .................................................................................................................. 10
Messages from control unit to sensors................................................................................. 10
5 Specifications.................................................................................................................................. 12
6 Reference Data............................................................................................................................... 12
HLS-440 Automotive Hydrogen Leak Sensor
Automotive Hydrogen Leak Sensor
Introduction
The HLS-440 Automotive Hydrogen Leak Sensor monitors hydrogen concentrations of 04.4% in air. The sensor is a safety sensor developed in accordance to IEC 61508 (SIL2)
and explosion protected according to ATEX ZONE 2. The predicted concentration is
transmitted to the host via the CAN bus interface.
Main features
• Excellent selectivity to Hydrogen.
• No humidity influence.
• Speed of response < 2s.
• Start-up time 1000ms.
• Accuracy ±3000 ppm at normal operation.
• Operating temperature range –40 to +110 ºC.
• Designed for SIL2 and ATEX zone 2.
• ISO 11898-2 CAN bus interface.
• ESD and EMC protection.
• Designed for IP67.
3
HLS-440 Automotive Hydrogen Leak Sensor
Overview
Gas inlet filter
Power and
CAN bus
connector
Mounting holes
4
HLS-440 Automotive Hydrogen Leak Sensor
Mechanical
Dimensions
Dimensions in millimeters. Tolerance ± 0. 1mm.
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HLS-440 Automotive Hydrogen Leak Sensor
Installation
The HLS-440 is designed for either a sealed installation against a wall (using a gasket) or
an open-air installation. The sensor can be oriented in any direction but the gas inlet must
not be blocked.
Retaining pins or bolts shall be max Ø5.5 mm.
Alt. 1
Alt. 2
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HLS-440 Automotive Hydrogen Leak Sensor
Electrical Interface
Electrical Connector
The sensor connector is a 6-pin MQS type. Matching receptacle is AMP p/n 1-967616-1.
Pin
4
1
2
5
6
3
Function
1
CAN – High
2
CAN – Low
3
Power UB0
4
Power UB1
5
Power UB2
6
GND
CAN bus interface
Physical interface
The physical interface is two-wire balanced, non-terminated. It is a high speed CAN interface
(ISO 11898-2) with bus bit rate at 500 kBit/s.
Bus Identification
Each sensor and the control unit is identified on the bus by the CAN identity, CAN ID. The
CAN ID is transmitted in the CAN data frame arbitration field. For the sensors the CAN ID
is determined by the configuration of the power supply feeds, UB0 (pin 3), UB1 (pin 4) and
UB2 (pin 5). The table below defines the sensor’s CAN ID, VB denotes a power input
connected to battery voltage level. Addresses are given in hexadecimal numbers and
denoted with a leading “0x”.
UB2
UB1
UB0
VB
VB
VB
VB
VB
VB
VB
VB
VB
VB
VB
VB
Sensor
Number
1
2
3
4
5
6
7
CAN ID
(M1)
0x640
0x648
0x650
0x658
0x660
0x668
0x670
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HLS-440 Automotive Hydrogen Leak Sensor
Messages From the Sensor
The main message sent from the sensor to the control unit is the Sensor Status Message,
hereafter referred to as the SSM.
After 700 ms from power-on of the sensor it will start sending the SSM frame as defined
below. The SSM, after this event, is transmitted periodically with a 100 ms interval until the
sensor is powered off. Besides the SSM, the sensor can also send a Wake-Up pulse. This
is described in detail in the Wake-Up function section. The Wake-Up pulse is separate from
the SSM and has no impact on the SSM.
The table below defines the data field of the SSM CAN data frame. The data field uses 8
bytes. The CAN ID as described earlier sets the arbitration field.
Parameter
name
Data
size
H2
Concentration
8
bits
Protection
Value 1
ACK limit
values
8
bits
8
bits
CRC16 Byte 1
(Higher Byte)
Protection
Value 2
8
bits
2
bits
3
bits
Sensor CAN ID
Msg. Counter
Sensor status
Physical
measurement
range
0 – 4.4 %
8
bits
2
bits
Part number
5
bits
CRC16 Byte 2
(Lower Byte)
8
bits
Value
range
b7
b6
b5
[20..240]
Lower Limit
b4
b3
b2
b1
b0
Byte
No
H2 Concentration
0
pv1
1
Upper Limit
0
0
CRC16
[1..7]
0
0
0
0
0
0
[0..255]
Ub1
4
Ub0
4
Msg Counter
[0..3]
[1..31]
3
pv2
Ub2
5
status
Part number
2
0
6
0
6
CRC16
7
H2 Concentration
0% is encoded with decimal number 20. 4.4% (44000 ppm) is encoded with decimal number
240. The relation between detected H2 concentration (in ppm) and concentration code as
signaled in the message is:
code = round(H2/200) + 20
H2 = (code – 20)*200
Where round() denotes rounding towards the nearest integer.
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HLS-440 Automotive Hydrogen Leak Sensor
Protection Value
The protection value offers a 10-bit consistency check of the transmitted concentration,
status and message counter. The following pseudo code describes the algorithm forming
the 10-bit value and how it is projected on to the protection value 1 and the protection value
2 bytes in the SSM.
code[7..0] denotes the set of 8 bits transmitted as code for representing the H2
concentration.
status[1..0] denotes the set of two bits transmitted as code for representing sensor status.
mgscnt[6..0] denotes the set of 7 bits transmitted as code for representing message counter.
pv[9..0] denotes the set of 10 bits forming the protection value.
pv1[7..0] denotes the set of 8 bits transmitted as code for protection value 1.
pv2[1..0] denotes the set of 2 bits transmitted as code for protection value 2.
Pseudo code
pv[9..8] = status[1..0]
pv[7..0] = code[7..0]
pv[9..0] = pv[9..0] + msgcnt[1..0]
pv[9..0] = NOT pv[9..0]
pv[9..0] = pv[9..0] + 1
pv1[7..0] = pv[7..0]
pv2[1..0] = pv[9..8]
Description
Assign two most significant bits of pv as the status bits
Assign 8 least significant bits of pv as the code bits
To pv add the number formed by two least significant bits of the
message counter
Perform bitwise inverse of pv
To pv add 1
Form protection value 1 of the 8 least significant bits of the 10bit protection value
Form protection value 2 of the 2 most significant bits of the 10bit protection value
Acknowledged Limit Values
The function of the acknowledged limit values is to reflect the limits used by the Wake-up
functionality. The values reported correspond to the values stored in the non-volatile memory.
CRC16
Byte 3 and byte 7 form a 16-bit CRC value. The CRC is CCITT CRC16.
Sensor CAN ID
Sensor CAN ID is defined by b2-b4, see chapter Error! Reference source not found. The
value sent is the Sensor Number.
Message counter
The message counter is incremented by 1 after each transmission of a SSM frame. After the
counter reaches 255 it wraps around and the next transmitted counter value becomes 0.
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HLS-440 Automotive Hydrogen Leak Sensor
Status
The table below defines the status encoding of b1 and b2:
Status
0
1
Encoding
B2:B1
0:0
0:1
2
1:0
3
1:1
Name
Description
No error
Minor error
Sensor fully functional
Main function ensured, but possible impairment
of measuring quality.
Main function ensured, but impaired (the sensor
should be replaced)
Sensor is not functioning correctly.
Minor
functional error
Fatal
functional error
Part Number
The part number defines the release number encoding of b3-b7.
Wake-up Function
The Wake-Up function is a feature of the sensor for sending a Wake-Up pulse on the CAN
bus, given a set of pre-requisites. The Wake-Up pulse is sent 800 ms after power-on.
If all of the following conditions are satisfied, the sensor will send the Wake-Up pulse and
then revert to normal operation. First, the function itself must be activated. Second, the
function is only checked after 800 ms from power-on. Third, the estimated Hydrogen
concentration at t = 800 ms must fall out of a specified concentration range. The Wake-Up
pulse corresponds to applying a bus dominant state for 2 ms. The activation of the WakeUp function and the setting of the concentration range are done with the command
described in the Messages from Control Unit to Sensors section.
At delivery the Wake-Up function is deactivated.
Messages from control unit to sensors
A single type of message is sent from the control unit to the sensors, hereafter referred to
as the Sensor Command Message, SCM. The SCM is identified on the bus by having the
CAN address 0x059. The CAN address is sent in the CAN data frame arbitration field.
The SCM consists of one CAN frame and is transmitted from the control unit when a
change in the stored limit values defining the concentration range used by the Wake-Up
function is desired.
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HLS-440 Automotive Hydrogen Leak Sensor
The table below defines the data field of the SCM frame. The data field uses up 8 bytes.
Parameter
Interval limits sensor 1
Interval limits sensor 2
Interval limits sensor 3
Interval limits sensor 4
Interval limits sensor 5
Interval limits sensor 6
Interval limits sensor 7
Message counter
b7
b6
b5
b4
b3
b2
b1
Lower Limit
Upper Limit
0
Lower Limit
Upper Limit
0
Lower Limit
Upper Limit
0
Lower Limit
Upper Limit
0
Lower Limit
Upper Limit
0
Lower Limit
Upper Limit
0
Lower Limit
Upper Limit
0
8 bit incrementing counter value
b0
0
0
0
0
0
0
0
Byte No
0
1
2
3
4
5
6
7
The encoding of the Lower and Upper Limits uses three bits and features the same
encoding given in the table below:
Lower limit
Upper Limit
b7
b4
b6
b3
b5
b2
H2 concentration %
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0.00
0.25
0.50
1.00
1.50
2.00
4.00
Function deactivated
The message counter must be incremented after each transmitted SCM. If a sensor detects a
non- incremented counter value (comparing last received) that SCM and all subsequent SCM
will be disregarded.
If either or both the Lower and the Upper Limit is set to 7 (1:1:1) for a specific sensor the
Wake-Up function of that sensor will be deactivated.
The sensor will start to listen for SCM’s after the first SSM has been sent. SCM frames sent
prior to this event will therefore be disregarded.
A successfully received SCM will result in the corresponding limit values being stored in the
respective sensor’s non-volatile memory. The stored values are then reflected in the next
SSM. However, as the actual use of the set range is only performed at a single time after
power-on and prior to SCM being accepted, it will not take affect, from a Wake-Up
functionality point of view, until the next power off/on cycle.
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HLS-440 Automotive Hydrogen Leak Sensor
Specifications
Sensor function
Target gas
Concentration range
Accuracy
Resolution
Speed of response (t90)
Speed of recovery
Cross-sensitivity
Start-up time
Expected lifetime
Hydrogen
0-4.4% H2 in air
+/- 3000ppm
200ppm
<2s
<10s
None towards HC, H2S, N2, CO, CO2, NOx
Low humidity influence during a H2 event. None in air.
1000ms
10 years
Safety
Safety Integrity level
Explosion proof
Self test/Error handling
Designed for SIL2
Designed for ATEX zone 2
Yes
Electrical
Supply voltage
Supply current
CAN interface
Programmable CAN ID
Connector
ESD/Reverse polarity
9 -16V
75mA typical
Version 2.0 ISO 11898
Yes
MQS 6-pin, AMP p/n 1-967616-1
Yes
Environmental
Operation temperature range
Storage temperature range
Humidity
Pressure
EMC
-40 to +110 ºC
-50 to +125 ºC
5-95% including condensation
70-130 kPa
GMW 3097
Mechanical
Dimensions (LxWxH)
Weight
Material
Filter membrane
IP code
82.2x42x17.3mm
50g
PBT +30% GF
Pall SUPOR 450R, 0.45 µm.
Target IP67
12
HLS-440 Automotive Hydrogen Leak Sensor
Reference Data
13
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USA
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